Latches for doors



April 29, 1958 H. THORNE 2,832,624

LATCHES FOR DOORS Filed Sept. 9, 1955 s Sheets-Sheet 1 April 29, 1958 H. THORNE 2,832,624

LATCHES FOR DOORS Filed Sept. 9, 1955 5 Sheets-Sheet 2 April 29, 1958 THORNE 2,832,624

LATCHES FOR DOORS Filed Sept. 9, 1955 3 Sheets-Sheet 3 United States Patent 2,832,624 'LATCHES FOR DOORS Harold Thorne, London, England Application September 9, 1955, Serial No. 533,357

Claims priority, application Great Britain December 13, 1954 Claims. (Cl. 292-169) This invention relates to latches for doors, particularly motor car or other vehicle doors, and its object is to provide simple means, operated by slight reverse movement of the usual latch-operating door handles, to dead-lock the latch against opening from one side of the door or the other.

The invention consists in a door latch, such as a latch for a vehicle door, comprising a casing, a spring loaded bolt movable in a rectilinear path, said bolt being retractable by a handle on the inner side of the door and by a handle on the outer side of the door, means for deadlocking the bolt, said means being moved to the deadlocking position by the operation of the inner handle in a direction reverse to normal, said means being released by the outer handle being operated normally.

Examples of the invention are illustrated on the accompanying drawings, in which:

Figure 1 is an elevation illustrating a latch wherein deadlocking may be elfected by the inner handle with subsequent release by the outer handle.

Figure 2 is a sectional side elevation, with outer handle detached, of another latch showing the bolt deadlocked by movement of the inner handle.

Figure 3 is a sectional side elevation of the same latch as Figure 2 but showing the bolt deadlocked by movement of the outer handle.

Figure 4 is a sectional side elevation, with outer handle detached, of a further latch in an unlocked condition.

Figure 5 is a sectional side elevation of the same latch as Figure 4 showing the bolt deadlocked by movement of the inner handle.

Figure 6 is a sectional side elevation of the same latch as Figures 4 and 5, but showing the bolt deadlocked by movement of the outer handle.

In the' form of the invention illustrated by Figure l, in which deadlocking of the latch bolt is effected by the inner handle and released by the outer handle, a pivoted deadlocking plate 12 is provided having a hooking formation or recess 13 adapted for engagement by a pin or projection 14 on the inner handle lever 15. When the lever 15 is moved in the reverse direction i. e. anticlockwise as seen in Figure 2, the pin 14 rides over the cam surface 16 of the plate, pivoting the latter against the action of a spring 17 until the hook snaps up and the recess 13 engages the pin 14 and locks the handle against movement, thus deadlocking the latch bolt 18 against operation by the inner handle.

Release of the handle lever 15 is effected by the outer handle for which purpose, the latch bolt lath 19 carries a projection 20 which underlies a cam surface 21 on the deadlocking plate. When the latch bolt is withdrawn by actuating the outer handle, the projection 20 riding along the surface 21 causes the plate 12 to pivot in a clockwise direction whereby the pin 14 is released from the recess 13 and the inner lever 15 returned to its normal position by the spring 22.

In this form of the invention deadlocking against opening by the inner handle may be effected by the outer 2 handle through a lever 23 coupled to the outer handle which lever is adapted to engage a projection 24 on the deadlocking plate 12.

When the outer handle is moved in the reverse direction, lever 23 pressing against projection 24 turns the locking plate into the position for engaging the pin 14 on the inner handle 13.

According to the form of the invention illustrated in Figures 2 and 3 the bolt may be deadlocked by either the inside or outside handle and released respectively by the outside and inside handle. These figures also illus trate a form of remote inside handle control. l

The inner handle a is coupled through a spring loaded positioning lever plate a and a link 0 to a bolt operating slider f. The slider is slotted at f for engagement with a fixed guide stud'g. The stud g also engages a slot d in the bolt lath. The bolt lath carries a 'stud w which engages in the slot 1" of the slider f for retraction of the bolt d upon a rearward pull on the slider.

The slider f has a downwardly extending notched spur e.

The bolt lath has a downwardly extending spur i;

The outer handle b is coupled to a bolt retracting lever 11 spring loaded by a torsion spring s'. The lever h operates against a stud w on the bolt lath.

A pivotally mounted detent c is provided with three radial arms c, 0 c and is spring loaded by a torsion spring s being biassed toward the lever h.

The detent is adapted to be operated by reverse move ment of either handle a or b to produce a deadlocking condition which prevents retraction of the bolt by the same handle, release being effected by normal operation of the other handle. Thus the latch can be deadlocke from either side of the door.

Figure 2 illustrates the deadlocking condition by reverse movement of the inner handle a which has been moved from the chain line position. Such movement causes a movement of the slider f towards the left in Figure 2 and brings the notched spur e to the left of the hooked arm a of the detent c. Retraction of the bolt by the slider f is thus prevented. I

Release of the bolt can now only be effected from the outside by handle b which on turning in the normal man ner causes the spur j in the bolt lath to engage the radial arm 0 of the detent and turn the detent clockwise as seen in Figure 2 and thus lower the hooked arm 0 and releasing the notched'spur e whereupon the slide 1 moves to the right in Figure 2 under the influence of the spring .9 which causes the roller r to move into the cam depression of the positioning lever plate a.

Figure 3 illustrates the position of parts when the outer handle b has been moved upwardly turning the lever h anticlockwise whereby the radial arm 0 of the detent moves into the path of the projection h of the lever thus preventing normal operation of the handle b and dead locking the bolt d.

Release is efiected by normal operation of the inner handle a through the slider and its slot connection with stud w on the bolt lath. The retraction of the bolt causes the spur j to move the detent by engagement with the radial arm thus moving the radial arm 0 away from the projection h, so that the lever h moves to its normal position under the influence of spring s.

By suitably selecting the strength of the spring s loading the lever h, rebound of the bolt when the door is slammed may rock the lever h forward by the stud W2 abutting against the lever whereby dead locking of the bolt from the outside may be effected.

Figures 4 to 6 illustrate a modified arrangement of the form of the invention shown in Figures 2 and 3 in which a simplified form of detent is used.

The coupling of the inner handle a to the bolt is by i I 2,832,624 Y 'PatentedApr. 29, 1958' means of a slider ,f and associated parts as in Figures 2 and 3 while the outer handle 12 operates the bolt through thepivoted lever h.

The detent c is now only provided with two radial arms c';.-,and.c. ,;the intermediate arm C2 and the spur y on the bolt tlath being eliminated. It will be noted also that the lever h is spring loaded by the detent spring s .The arm a is provided with a cam surface with which a .projection It on the lever 11 is adapted to cooperate.

Under normal conditions of the handle b the projection it engages the cam surface 0 but when dead locking is effected by handle I; and the projection h is raised the arms moves beneath the projection It and further operation by handle b is now. prevented.

Figure 4 shows the parts in their normal position.

. In Figure 5 deadlocking has been eflfected by a reverse movement of the inner handle a causing a latching engagement of the spur e on the slider and the hooking arm c of .the detent. Release from this position is effected by normal operation of the outer handle 12 which causes the projection h to move down the cam surface 0 pivoting the detent in a clockwise direction and disengaging the arm 0' from the spur c.

When dead locking has been effected by a reverse movement of the outer handle (see Figure 6) the detent 0 turns anticlockwise to bring the arm c beneath the projection i and thus prevent operation of the bolt by the outer handle I).

In order to release the outer handle b a slight reverse movement is imparted to the inner handle a which causes the wedge shaped toe e, of the spur e to ride on the surface c of the hooking arm 0 whereby the detent is pivoted in a clockwise direction to remove the arm c from the projection h. The lever h is thus free to return by a spring (not shown);

The latch bolt d may now be actuated by either handle a or b.

- ,I claim:

1. A door latch such as a latch for a vehicle door, comprising a casing, a spring loaded bolt movable in a rectilinear path, said bolt being retractable by a handle on the inner side of the door and by a handle on the outer side of the door, means for dead locking the bolt, said means being moved to the dead locking position by the operation of the inner handle in a direction reverse to normal, said means being released by the outer handle being operated normally. V

2. A door latch as claimed in claim 1, wherein the deadlocking means comprises apivotally mounted bell crank tion when the handle is moved in a reverse direction whereby to prevent normal operation of said handle, a projection on the bolt adapted to engage said cam surface, said projection becoming operative upon actuation of the outer handle to release the bolt whereby the inner handle is released.

3. A door latch as claimed in claim 1, wherein the dead locking means comprises a pivotally mounted detent having three arms, a spring loaded positioning lever coupled to the inner handle, a link coupling the positioning lever to a bolt actuating slider, a spur on the bolt cooperating with the center arm of the detent, said slider having a notched spur adapted to cooperate with one outer arm of the detent, a bolt retracting lever coupled to the outer handle, a projection on the bolt retracting lever adapted to cooperate with the other outer arm of the detent, the arrangement being such that dead locking is effected by either of said outer arms engaging the associated parts by reverse'movement of either handle, while release is effected by the other handle being moved in the normal direction to cause the spur on the bolt 'to engage the center arm of the detent to pivot such to release the appropriate outer arm.

4. A door latch as claimed in claim 3, wherein the bolt retracting lever is spring biased, the spring being of a strength so that the rebound of the bolt when the door is slammed causes the lever to move to a dead locking position.

' 5. A door latch as claimed in claim 1, wherein the dead locking means comprises a pivotally mounted detent having two arms, a spring loaded positioning lever coupled to the inner handle, a link coupling the positioning lever to a bolt actuating slider, a spur on the slider adapted for latching engagement with one arm of the detent for dead locking by the inner handle, a spring loaded retracting lever coupled to the outer handle, a projection on the spring loaded retracting lever adapted for engagement with the other arm of the detent for dead locking the outer handle, a cam surface on said other arm, said projection being operated to engage said cam surface, release of the dead locking condition being effected by normal operation of the outer handle.

References Cited in the file of this patent UNITED STATES PATENTS 

